The politics lead, Donald Trump soaring, crushing the field, and leading the outsiders at the front to the GOP race in a brand-new poll, so what happened to the guys who were supposed to be on top?

The world lead, propaganda machine in overdrive. North Korea warns the United States it will attack with invincible power. This is the same country that would have you believe their Dear Leader doesn't go to the bathroom. How seriously should the Pentagon be taking this threat?

And the national lead, accusations of rape at an elite New England prep school coming to light during a trial involving a 15-year-old girl. Were very privileged upperclassmen using girls as notches on their belts?

Happy Monday. Welcome to THE LEAD. I'm John Berman. Jake Tapper is off today.

Our politics lead, a superhero unmasked. Donald Trump confirming to a child over the weekend that he is Batman. You know, it makes sense, a New York City tycoon, with absurd wealth, with his own fleet of aircrafts who wants to save Gotham and make America great again, but if you listen to his Republican rivals, they say Trump is no Dark Knight. No, they say he better resembles the caped crusader's arch nemesis the Joker, that he's spawned anarchy in the presidential race, robbing attention from others, such as Jeb Bush, and kidnapping Scott Walker's lead in Iowa, and plus there is the hair.

He has a new immigration plan or statement just unleashed yesterday, and all the other candidates are bound to be asked about it whenever they face the press next.

I want to bring in CNN senior Washington correspondent Jeff Zeleny.

Jeff, you just got back from your home state of Iowa, the Iowa State Fair, and you saw all of this in person. The Donald Trump summer continues. JEFF ZELENY, CNN SENIOR WASHINGTON CORRESPONDENT: John, it does.

I have been to a lot of Iowa State Fairs. But I can tell you this is something week like we have never seen before. There were crowds swarming around Donald Trump, more of like a celebrity than a candidate. Well, of course, he's both. That's something that Republicans are trying to grapple with. Up until now, they have given up the idea his star will fade at the end of the summer.

They're now settling in for the long haul, even as they worry his new immigration plan and other policies could keep them from expanding the party's appeal and even winning the White House.

(BEGIN VIDEOTAPE)

ZELENY (voice-over): Donald Trump arrived for his civic duty in a black limousine, reporting for jury duty today in New York.

DONALD TRUMP (R), PRESIDENTIAL CANDIDATE: Something we have to do.

ZELENY: A Trump-sized spectacle outside, but far quieter inside, as captured on Snapchat by a prospective fellow juror.

A break from the campaign trail, where Republicans are rendering a winning verdict on Trump. He's leading another national poll, solidifying his role as the GOP front-runner. In a whirlwind weekend stop at the Iowa State Fair, he said he would spend $1 billion of his own fortune on the campaign.

TRUMP: I make $400 million a year, so what difference does it make? What I want to do is I want to make the country great.

ZELENY: Trump is also offering new read for conservatives, a hard- line immigration plan. His six-page proposal calls for an end to birthright citizenship, a provision in the 14th Amendment to the Constitution that grants citizenship to those born in the U.S.

He and other political outsiders are turning this race upside-down, leading an insurgency against their Republican rivals. A new FOX News poll shows Trump leading with 25 percent followed by Ben Carson at 12, Ted Cruz at 10, and Jeb Bush falling into fourth place.

BEN CARSON (R), PRESIDENTIAL CANDIDATE: I believe that we, the American people, have the ability to solve the many problems that face us.

ZELENY: Carly Fiorina is getting another look, too.

CARLY FIORINA (R), PRESIDENTIAL CANDIDATE: I was asked on a national television program whether a woman's hormones prevented her from serving in the Oval Office.

ZELENY: Wisconsin Governor Scott Walker has led the way in Iowa for most of the year. Today, he was heckled by labor activists at the state fair. GOV. SCOTT WALKER (R-WI), PRESIDENTIAL CANDIDATE: I am not

intimidated by you, sir, or anyone else out there. I will fight for the American people over and over and over and over again.

ZELENY: But Walker and other top Republicans are being tested by an anti-establishment electorate, driving their poll numbers to single digits.

ZELENY: A long haul now overtaken by Trump on land and now in the sky.

TRUMP: Let's give them a helicopter ride. OK?

UNIDENTIFIED CHILD: Mr. Trump.

TRUMP: Yes?

UNIDENTIFIED CHILD: Are you Batman?

TRUMP: I am Batman.

(LAUGHTER)

(END VIDEOTAPE)

ZELENY: Those rides on that $7 million Trump helicopter will surely never be forgotten. But it's an open question whether all of the people who turned out to see him at the fair will actually turn out and support him in February when the Iowa caucuses officially start the 2016 voting

[16:05:03]

But, John, the people I talked to on the ground in Iowa said they were very intrigued by him and his policies. They like how much hell he's giving the party in the words of some voters, but they're still taking a wait-and-see approach. And that's what we have to do as well, take a wait-and-see approach to see how his candidacy develops.

BERMAN: Because everyone loves Batman.

Jeff Zeleny, thanks so much for being with us. Appreciate it.

The one thing Republicans can agree is on Hillary Clinton's e-mails. They all say she does need to face more scrutiny over how she handled her correspondence at the State Department. And now the State Department disclosing today more of her e-mails will be put under the microscope.

Intelligence officials have referred hundreds of documents for further review, because they might contain classified information.

PAMELA BROWN, CNN JUSTICE CORRESPONDENT: We have learned today, John, that 305 documents from Hillary Clinton's private server have been referred to various intelligence agencies for consultation to determine whether the contents are classified.

This is according to a court filing from the State Department today, and this comes after intelligence community reviewers from five different agencies joined the review process of Clinton's e-mails. This court filing today says, "As of a sample of approximately 20 percent of Clinton's e-mails, the intelligence community reviewers have only recommended 305 documents, approximately 5.1 percent for referral for their agencies for consultation."

So this filing is basically an update for a federal judge on review efforts in response to a Freedom of Information Act lawsuit, and Hillary Clinton has repeatedly denied sending or receiving information marked as classified through her personal server. Here's what she said over the weekend in response to the controversy.

(BEGIN VIDEO CLIP)

HILLARY RODHAM CLINTON (D), PRESIDENTIAL CANDIDATE: Most importantly, I never sent classified material on my e-mail, and I never received any that was marked classified.

So, I'm going to let whatever this inquiry is go forward, and we will await the outcome of it. The State Department has confirmed what I just said to you.

(END VIDEO CLIP)

BROWN: She also said this is not about the e-mails, it's about politics. It's unknown at this point if any of the 305 flagged e- mails contained classified information, but it comes at a time when the FBI is investigating the security of Hillary Clinton's private server she kept in her New York home after the intelligence community inspector general identified two e-mails among a sample of 40 work- related e-mails that should have been marked top secret.

Bottom line, this doesn't seem to be going away for Hillary Clinton any time soon.

BERMAN: No. The key here is she says she received no e-mails that were marked classified, but whether they were classified, it may be a different story altogether. That's what this investigation will determine.

Pamela Brown, thank you so much.

BROWN: Thank you.

BERMAN: Still more big political news today. President Obama finds himself stuck in the middle, on one side, Joe Biden, his number two, his most trusted confidant, on the other end, Hillary Clinton who has a more complicated relationship with the current occupant of the White House.

But all the president's friends, all the president's fund-raisers, at least most of them, are now Hillary Clinton's friends and fund- raisers. That could leave the vice president with little staff and even less money to make a play at The Oval Office.

CNN senior White House correspondent Jim Acosta is live in Martha's Vineyard for us.

Jim, you have been asking around with some of the president's most trusted advisers, and you have new information on how they view a potential Biden candidacy.

JIM ACOSTA, CNN SENIOR WHITE HOUSE CORRESPONDENT: That's right, John.

As Joe Biden might say, it would be a big deal if the vice president decides to run for the White House, but there's one potentially major obstacle standing in the way beyond Hillary Clinton. A well-placed source tells CNN there are worries inside the White House that a Biden candidacy won't end well.

(BEGIN VIDEOTAPE)

ACOSTA (voice-over): He could be the straight-talking "shoot from the lip" candidates many Democrats are craving as an alternative to Hillary Clinton.

JOSHUA ALCORN, SENIOR ADVISER, DRAFT BIDEN: Joe Biden is the original authentic candidate. He is the guy who can walk around and talk to people like you and me and talk to people in Iowa and South Carolina and all over the country and really connect with them on a visceral level.

ACOSTA: A movement to draft Joe Biden for president is gaining momentum, collecting some 200,000 signatures. And the vice president is fueling speculation himself, considering a run while on vacation in the early primary state of South Carolina.

Potential rival Bernie Sanders, who is gaining on Clinton, said he would welcome Biden to the race.

SEN. BERNIE SANDERS (VT-I), PRESIDENTIAL CANDIDATE: He is a very decent guy. He's a friend of mine. If he gets in, that's great. If he doesn't get in, that's great. That's his decision.

ACOSTA: But not everybody in the Democratic Party is on board. At the White House, a well-placed Democratic source said there are concerns a Biden candidacy would end badly, damaging his image as an elder statesman, adding, "I'm not getting any sense of a Joe Biden caucus inside the White House."

But Biden is also seen by some as a safety net for a party growing nervous about Clinton's use of her private system as secretary of state. Before the Clintons and the Obamas linked up for golf and galas on Martha's Vineyard over the weekend, she accused the GOP of ginning up controversy. [16:10:09]

CLINTON: I have just provided my server to the Justice Department, but here's what I won't do. I won't get down in the mud with them.

ACOSTA: Then she joked about her new favorite social media app, Snapchat.

CLINTON: I love it. Those messages disappear all by themselves.

(LAUGHTER)

ACOSTA: Still top Democratic sources say Clinton remains the party's best hope for protecting and expanding President Obama's legacy. There is also deep affection for the vice president at the White House, where it's clear officials are giving Biden time to grieve his son Beau's recent death and weigh his own political future.

ERIC SCHULTZ, WHITE HOUSE DEPUTY PRESS SECRETARY: The president and the vice president are very close. And the president has said that he believes his best political decision, the smartest political decision he's ever made was choosing Joe Biden to be his running mate.

(END VIDEOTAPE)

ACOSTA: Now, a source familiar with the vice president's thinking says Biden's decision is expected at the end of the summer, adding, don't think August, think late September. If Biden runs, it would be a huge dilemma for the president. After appointing a team of rivals, he may have to choose between two of them -- John.

We want to talk about this and everything 2016 with CNN political commentators Kevin Madden and Donna Brazil.

Thanks so much for being with us.

(CROSSTALK)

BERMAN: Before we get to Joe Biden and Hillary Clinton's e-mails, I have to give you breaking Donald Trump news. He had jury duty in New York City today. He did not get picked, ladies and gentlemen. He was not selected to sit on the jury.

DONNA BRAZILE, CNN POLITICAL ANALYST: How do you say that? That is fantastic.

(CROSSTALK)

BRAZILE: Terrific.

BERMAN: So there's that.

Let's talk about Joe Biden, Donna. Jim Acosta's report there was very interesting. Jim has been talking to White House insiders, Democratic officials. And they're really not jumping up and down. Democrats I speak to, you can't find anyone seriously on the inside who says they think Joe Biden will run or even really that they're hoping to see it happen right now.

BRAZILE: Before we throw cold water, maybe -- I shouldn't throw cold water on it.

First of all, he's beloved a figure in the Democratic Party. He has been a champion for the middle class before anybody found talking points to found about job security and job creation. Joe Biden is a natural politician, and if he decides to run -- and it's a big if, because, as you know, he's mulling over this, he's talking with his family, he's trying to look at how he can get into the race at this point.

If he decides to run, he will have support. Maybe not as much as the other two front-runners, Secretary Clinton and Senator Sanders. But Joe Biden should not be ruled out, because he cares about this country, and he's a leader. He's a fighter.

BERMAN: There are people who say they will support him in some of the key states, South Carolina. But there's hardly a Joe Biden caucus right now. When do you think he has to decide by, Donna?

BRAZILE: By October, because, look, you got to start filing. You got to begin to put together a slate of delegates.

I know from experience, flying on Air Force Two is very expensive, you have got to put together a staff and you have to figure out how you will get from point A to point B. But no one should rule it out. Joe Biden, this is his decision, his future.

And let me say something. Joe Biden is one of the nicest people I have ever met in American politics.

BERMAN: You hear that on both sides of the aisle.

BRAZILE: Yes.

BERMAN: Kevin, I want to talk about the person Joe Biden could potentially possibly run against.

Hillary Clinton, we just learned, Pamela Brown reporting, 300 e-mails will be reviewed to see if there was classified information on them. She has repeatedly said that she received nothing that was marked classified. She said that. But this weekend in Iowa, she also joked about the e-mails on the stump. I want to listen to that.

(BEGIN VIDEO CLIP)

CLINTON: By the way, you may have seen that I recently launched a Snapchat account. I love it. I love it. Those messages disappear all by themselves.

(END VIDEO CLIP) BERMAN: I want to talk about the political calculation there, because it seems to me what she is saying is, look, if you hate me over the e- mails, if you have questions about the e-mails, you're going to hate me over the e-mails, and you have questions them

But if you support me, then I'm going to tell this joke to make you laugh.

KEVIN MADDEN, CNN CONTRIBUTOR: Yes.

BERMAN: Should she be making light of this thing?

MADDEN: I don't believe so.

But I see the political calculation here, which is that this is designed to distract away from this. From the beginning, the Clintons have tried to say this is nothing, the voters don't care about this, so what they're trying do is make fun of it. It's the new version of this vast right-wing conspiracy, and they're trying to send a message to the base that this is all Republicans against me, and I'm not going to let them get me down.

But, look, the FBI -- I think it's a message that falls flat, because the FBI is not partisan. The FBI is looking at this from a legal standpoint.

(CROSSTALK)

BRAZILE: John, she was asked to turn over her e-mails. Four secretaries of state, turn them over. She turned them over, and you know what?

They're sending a few of them back because they're personal, but she's turning them over.

(CROSSTALK)

BERMAN: And these are being investigated.

(CROSSTALK)

[16:15:00] BERMAN: And someone is going to rule whether there was classified information.

BRAZILE: Absolutely.

And you know what? We're not -- before it's released to the public, of course you want to make sure that if -- if it's classified information.

Look, I have been through a security clearance. If it's classified, you want to make sure it's not released in the public.

But, you know, I take Dianne Feinstein's word. You know, she's been on intelligence, she's seen some of this stuff, and she's said, look, at the time they e-mails were sent, they are not marked classified. So, we could get into a new classification because they went to Hillary Clinton, we should put a big CCC, you know?

KEVIN MADDEN, CNN POLITICAL COMMENTATOR: All of that is outside -- all of that is outside the bigger question, which why she even set up an email to begin with?

BRAZILE: Well, she's already said that. She's already answered that.

MADDEN: You go back to the first press conference a few months ago --

BRAZILE: I remember.

MADDEN: -- everything that she said in that press conference has turned out to be false.

BRAZILE: No, it has not.

MADDEN: Yes.

BRAZILE: That's what Trey Gowdy is saying.

By the way, we're running -- on the house side, they're running a taxpayer-funded, $4 million campaign to smear Hillary Clinton. This should be focused on what happened in Libya, what happened to our four Americans who died, but rather it's become the Hillary Clinton smear campaign. That's my position.

MADDEN: And this is all because of Hillary Clinton. If she had used her own State Department e-mail, we wouldn't be here. But because Hillary Clinton tried to use a separate serving in order to avoid the same scrutiny that other government officials --

BRAZILE: No, no. That's not --

MADDEN: -- have to go through.

(CROSSTALK)

BERMAN: We're going to leave it here, but I will say, this is why a lot of Democrats saying at least they're discussing Joe Biden right now.

BRAZILE: Democrats always get a little, you know, weary, and unlike the Republicans where you have a lot of people running, we have five quality candidates and I will pick them any day over some of the Republicans.

BERMAN: Donna Brazile --

MADDEN: One of them who is a devout socialist, though.

BERMAN: -- and Kevin Madden, thank you for being with us. Appreciate it.

MADDEN: Good to be with you.

BERMAN: All right. In our world lead, a huge bomb blast in the Times Square of Thailand. More than a dozen people are dead, including foreign tourists. But who is behind this attack? That's next.

(COMMERCIAL BREAK)

[16:21:06] BERMAN: Welcome back to THE LEAD.

Topping the world lead right now, a bomb blast tears through the heart of equivalent of Bangkok's Times Square.

Wow, you can see it right there, the dramatic dash cam video just into CNN. It captured the huge explosion during the evening rush hour. The blast has killed at least 18 people, wounded more than 100 others. The attack happened near a Hindu shrine that's very popular with locals and very popular with tourists, right in a bustling part of Thailand's capital.

I want to get straight away to CNN's Andrew Stevens live for us in Bangkok.

Andrew, walk us through what happened and what we know about this bombing?

ANDREW STEVENS, CNN INTERNATIONAL CORRESPONDENT: Well, first of all, John, as you say, this is known as the Times Square of Bangkok. A lot of tourists would know this area very well. There's the Intercontinental Hotel, Grand Hyatt all around here.

And if you look behind me, you see the bright lights, that is where the Erawan shrine is. And what happened is 7:00, which is the busiest time of the day, a blast was detonated just right off that shrine, and 18 people died. Four people were killed instantly. There are no claims at this stage of any responsibility.

There have been suggestions from the police here that it could have been targeting foreigners, particularly Chinese. It could be to do with the local political situation. No one is claiming responsibility. So, at this stage, very difficult to draw any conclusions.

But it's an absolute shock of people who lived here. We've never seen, people in Bangkok has never seen anything of this magnitude, this sort of attack in an area which is so popular with locals, with tourists. A lot of people go to that shrine. And if you imagine the scene, 7:00 in the evening, there would have been a line of flower sellers here, people going in to offer a flower to the god in the hope of a blessing, and then carnage, John.

BERMAN: So much devastation. Andrew Stevens, thank you so much.

I want to talk more about this. Joining me is CNN global affairs analyst, managing editor of "Quartz", Bobby Ghosh.

Bobby, appreciate you being here. As Andrew just said, no one has claimed responsibility, but who would want to do something like this? An attack during rush hour, during right next to a very, very popular shrine, tourists flock to it. Who are the potential players here? BOBBY GHOSH, CNN GLOBAL AFFAIRS ANALYST: Well, I think, John, the

most -- the first suspicions would go to one of two groups. There is an Islamist insurgency that's taking place in southern Thailand, but this is not their style at all.

The insurgents, their complaints are very local, their fight against the state has been very local and they have tended to attack military and security targets. They have not really committed a terrorist attack of this nature against civilians, much less tourists. This does not seem to bear their fingerprints.

The other most obvious goes to the political situation. There's been instability in Thailand for a while. The military took over a couple of years ago, and there are political groups that are opposed to military rule, but they are democrats. This is not their style, either. They don't go around bombing innocent civilians and hurting Thailand's economy, which this will do, is the last thing that they would want.

So, basically, the two groups within the country that might attract attention and suspicion, this really does not bear their fingerprint. So, is it -- could it be an outside group? Could it be ISIS? Could it be Al Qaeda?

Now, in recent weeks, security chiefs in two neighboring countries, Malaysia and Indonesia have issued warnings saying they were picking up some signals that foreign terrorist groups wanted to commit an attack in the region.

[16:25:02] They didn't mention Thailand, but perhaps, just perhaps, this is what we are seeing now.

Is there a history of attacks in that city to go after perhaps more international victims?

GHOSH: Not so much in bang com. We've seen it in the neighborhood. You will remember in 2002 the horrific attacks again tourist targets in the island of Bali, in Indonesia, and then in 2005 again in Bali, and the targets were tourist targets, specifically westerners and perhaps specifically Australians.

But attacks of this nature have not taken place in Thailand, certainly not of this kind of ambition and this kind of scale. And it is very clear that they were meant to hurt as many people as possible.

BERMAN: Yes.

GHOSH: This is not an attack against a religious group per se. You mentioned this is a Hindu shrine, and it is, but the majority of people who go worship there are not Hindu. They're actually Buddhists, local Thai people, as well as foreign tourists who go there out of curiosity, to imbibe a little bit of Thai culture. This does not seem like a religious target at all. BERMAN: No, it certainly looks like an attack designed to kill as many people as possible.